Internal combustion engines are often used to power watercraft, including those watercraft known as personal watercraft. These watercraft include a hull which defines an engine compartment. The engine is mounted within the engine compartment and arranged to drive a water propulsion device.
Exhaust which is generated by the engine is routed through an exhaust system to a point external to the watercraft. Generally, this is accomplished by routing the exhaust into the water in which the watercraft is operating. When the water propulsion device is a water jet propulsion device, the exhaust may be routed into the water which is being expelled from the jet propulsion device to propel the craft.
These exhaust systems generally include a first portion which is connected directly to the engine. Exhaust flows from each combustion chamber of the engine through an exhaust passage into this first portion. A second portion of the exhaust system is connected to the first portion and leads to the exhaust discharge.
The first and second portions of the exhaust system are generally connected with a flexible coupling member. This coupling permits expansion of the exhaust system portions due to temperature changes and the like.
A problem exists that the durable life of the coupling member is shortened significantly due to the transmission of engine and watercraft vibration through the exhaust system portions. These vibrations may eventually cause the coupling to break, causing exhaust leaks in the exhaust system. In addition, in those instances where coolant flows through a coolant jacket corresponding to the exhaust system, the rupture of the coupling may cause a corresponding coolant jacket rupture.
An exhaust system for an engine of the type utilized to power a watercraft which overcomes the above-stated problems is desired.